In the preparation of a large bird for sale it is standard to cut the bird up after slaughter into several pieces. A turkey is cleaned by removing the viscera and then rinsing the animal. Then the bird is hung from a conveyor chain which moves it through a plurality of stations at which pieces are cut off it, it is deboned, and so on. Clearly this process requires a substantial amount of manual work and has the considerable disadvantage that the quality of the end product depends directly on the abilities of the people doing the various steps. Furthermore a normally significant amount of meat is left hanging on the body or lodged in cavities thereof.
The general morphology of a fowl is comprised generally as follows:
The front end of the thorax is closed by a bony architecture defined by the vertebral column, the base of the neck of the animal, the clavicles, and the coracoids.
The central part of the body is defined by the vertebral column, the ribs, and the sternum.
The rear part of the more or less concave pelvis ending in the pygostyle and the ischium includes joint regions for the femurs as well as the iliac fossae.
Because of the complexity of this structure it is very difficult to completely separate the meat from the skeleton. The coracoids are among the most difficult elements because they form parts that project from the skeleton and define therewith hollows from which it is difficult to extract the meat. It has thus been proposed to cut or to dislocate the coracoids and then to proceed during the subsequent cutting-up of the fowl to tearing them out in order to be able to recover meat lodged in the hollows, that is the breast meat, the back meat, and even the coracoid meat. The aim is to use a tool that can move as close as possible to the body so as to facilitate removal of the meat therefrom.
There are several main ways to achieve this goal:
In one system the tendons at the junction between each coracoid and the sternum are cut, the coracoids are dislocated and then the wings are ripped off With the shoulder blades.
In a second system the coracoids are cut before tearing off the wings so that the parts of the coracoids adjacent the sternum remain on the body.
In a third system a cut is formed at the level of the joint of each wing before the wings alone are torn off.
None of these arrangement has been reduced to an easily performed if not automated procedure. Accordingly removal of the wing structure from a bird is often a bottleneck in a meat-packing operation.